docs: def _check_hint_bounds(self, ds):
          '''
          Checks for variables ending with _bounds, if they are not cell methods,
          make the recommendation
  
          :param netCDF4.Dataset ds: An open netCDF dataset
          :rtype: list
          :return: List of results
          '''
          ret_val = []
          boundary_variables = cfutil.get_cell_boundary_variables(ds)
          for name in ds.variables:
              if name.endswith('_bounds') and name not in boundary_variables:
                  msg = ('{} might be a cell boundary variable but there are no variables that define it '
                         'as a boundary using the `bounds` attribute.'.format(name))
                  result = Result(BaseCheck.LOW,
                                  True,
                                  self.section_titles['7.1'],
                                  [msg])
                  ret_val.append(result)
  
          return ret_val